Causes of wear and tear of circulating fluidized bed boilers in thermal power plants and solutions

       China's current thermal power plants play a top-down role in power supply, and thermal power plants will still account for a high percentage for a long time to come. In the production of power supply in thermal power plants, boilers play an important role.

　　With the continuous development of industry, boilers are also progressing, more environmentally friendly and energy efficient circulating fluidized bed boilers were born, but due to the characteristics of circulating fluidized bed boilers themselves lead to it will wear. Circulating fluidized bed wear will directly affect the thermal power plant industrial production and life safety, this paper will analyze the causes of circulating fluidized bed boiler wear, and put forward effective circulating fluidized bed boiler anti-wear, which will be of great significance to the thermal power plant circulating fluidized bed boiler.

　　In the daily operation of circulating fluidized bed boiler, the solid bed material containing fuel, fuel ash, limestone and its reaction products are in the closed circulation circuit of furnace chamber-separator-returner-chamber in a non-stop high temperature circulation flow, and high efficiency combustion and desulfurization reaction is carried out at 850-950℃ in the furnace; therefore, a certain amount of wear will be generated in the corresponding parts of the circulation circuit.

　　Long-term wear and tear of the boiler, in the work as a person working with a disease, low efficiency at any time can occur safety accidents. This will have a huge impact on thermal power plants, so boiler anti-wear must be paid attention to.

　　Causes of wear of circulating fluidized bed boiler

　　The cause of wear and tear has a certain relationship with the pulverized coal furnace. The pulverized coal road will produce a large number of solid particles in operation, and when these solid particles run through the water-cooled tube, they will produce a lot of friction and scouring on the inner tube wall, thus leading to the wear and tear of the water-cooled tube. In addition, because the boiler itself has the function of internal circulation, so when these solid particles fall back in the process of operation, it will produce a secondary scouring of the inner wall, causing more wear. Especially at the location where the water-cooled tube and refractory layer meet, the scouring is more serious because of its prominent location.

　　Influence of flue gas flow rate

　　In the process of boiler operation, a large amount of flue gas will be generated, in which the greater the flow rate of flue gas, the more serious for the boiler wear, if the air volume is large, it will increase the degree of wear. In the case of increased secondary air volume, it will form a great disturbance to the combustion condition in the boiler, thus accelerating the wear and tear.

　　Effect of flue gas particle concentration

　　The process of fuel combustion will produce a large amount of flue gas, and in these flue gas will contain a large number of particles, if the amount of flue gas is large, the larger the particles contained in it, in the process of eliminating flue gas, these particles will cause impact on the boiler tube wall, damaging the inner wall of the boiler. Especially this boiler also has the function of internal circulation, so it increases the scouring of the interior. The greater the concentration of particles in the flue gas, the greater the wear and tear on the boiler.

　　Influence of the nature of the fuel

　　The operation of the boiler requires the combustion of fuel to provide power, and the particles and ash produced by the combustion of fuel will cause wear on the inner wall of the boiler, and the hardness and degree of these particles and ash produce different degrees of wear. Therefore, the nature of the fuel is very important in determining the nature of the particles and ash produced, thus controlling the degree of wear on the inside of the boiler.

　　Boiler installation and quality maintenance

　　The installation quality of the boiler directly affects the later operation efficiency. If the quality of the installation is not up to the standard, then in the later operation, it will cause the leakage of particles and intensify the wear and tear of the boiler. At the same time the installation quality as well as the maintenance is not qualified, for the later operation of the boiler will leave safety hazards.

　　The impact of the boiler's own power field

　　Due to the limitations of the boiler itself in the internal structure, it leads to uneven flow of flue gas emission process, which causes different degrees of wear on the internal structure. The degree of wear is greater where the flue gas flow is high, which is related to the boiler's own dynamic field.

　　Anti-wear measures for circulating fluidized bed boilers

　　In the normal operation of circulating fluidized bed boilers, strengthening the anti-wear measures of the boiler can not only improve the thermal efficiency of the boiler, but also extend the service life of the boiler on the original basis, and at the same time of saving cost investment, it also guarantees the economic benefits of boiler combustion.

　　Thermally conductive grille anti-friction technology.

　　Thermally conductive grille anti-wear technology is an active anti-wear technology that is installed on the surface of the water-cooled wall along the horizontal and vertical directions, with alloy grille plates to form a mesh grille, blocking the formation of high-speed wall flow, optimizing the flow field on the surface of the water-cooled wall, eliminating local eddy currents, reducing the velocity of gas-solid two-phase flow against the wall, and reducing the cutting force of material particles on the water-cooled wall, so as to effectively control the wear problem of the water-cooled wall.

　　Circulating fluidized bed boilers can be safe and efficient operation for thermal power is of paramount importance, thermal power plant boilers in daily operation wear and tear is an inevitable thing. Power plants must do a good job of daily anti-wear measures to effectively control the degree of boiler damage prevention and improve boiler efficiency and safety productivity.

　　Circulating fluidized bed boilers do a good job of anti-wear not only to improve production and safety, but also to extend the life of the boiler, can be said to kill many birds with one stone.